It is well known that fluorine ions are applied to tooth tissue to provide reinforcement, and dental materials in which fluorine ion-releasing materials are blended are already being used to prevent and inhibit caries.
As a representative method to prevent dental caries, a method of caring a dental plaque, a method of utilizing fluorine, a sealant method, or a dietary control method. Among them, starting from the research disclosed in 1938 by Dean, relating to a concentration of fluorine ions in drinks is inversely proportional to the occurrence of caries, a great amount of research using fluorine to prevent dental caries has been conducted.
For example, particularly, in Japanese Laid-Open Patent Application No. sho 57-88106, a dental material containing a homopolymer of (meth)acrylic acid fluoride or a copolymer of (meth)acrylic acid fluoride and a (meth)acrylic acid lower alkylester as a fluorine ion-sustained release material is disclosed, and in Japanese Laid-Open Patent Application No. Hei 7-101819, a dental resin composition containing a specific fluorine-containing phosphazene monomer as a fluorine ion-sustained release material is disclosed.
Fluorine prevents tooth decalcification and enhances remineralization, thereby preventing caries in healthy teeth or teeth in which caries has occurred. That is, when fluorine ions are applied to an enamel of a tooth surface and substituted with a hydroxide group of an enamel hydroxyapatite crystal, they can stabilize the apatite crystal, and thus increase acid resistance of teeth, thereby preventing dental caries. When the fluorine is administered during formation of enamel, a concentration of fluorine ions of the enamel is increased, the acid resistance is increased, and the occurrence of caries is inhibited. Moreover, as a subsidiary means, fluorine application is developed.
The fluorine application is used as a method of preventing caries or treating sensitive teeth by increasing the concentration of fluorine ions of the enamel.
The fluorine application is performed using a fluorine gel or a fluorine varnish. However, since it is noted that the fluorine gel is hydrophilic, has a short contact time with teeth, presents a risk when swallowed during application, and discolors and erodes previous esthetic restoration, recently, the use of fluorine varnish has been increasing.
In case of the fluorine varnish, the first generation varnish, Duraphat (Colgate-Palmolive, USA), was first developed and commercially available in Europe in the late 1960s, and an individually packed third generation fluorine varnish has since been developed. The fluorine varnish can allow fluorine to bind to a natural resin having high adhesion to teeth to contact a high concentration of fluorine with the teeth for a long time, thereby increasing an opportunity to accumulate calcium fluoride on a surface of the teeth, and thus it has a short application time, and a simple technique.
However, the fluorine varnish has a resin as a main component, and thus causes inconveniences such as temporary discoloration of teeth, an unpleasant flavor, and sticky texture in application. In addition, the fluorine varnish does not stay attached to the teeth surface for a long time and is easily removed due to saliva or food, and thus a suitable fluorine concentration cannot be maintained in an oral cavity for a long time.